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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: andrea@betterlinux.com
Cc: akpm@linux-foundation.org, minchan.kim@gmail.com,
	riel@redhat.com, peterz@infradead.org, hannes@cmpxchg.org,
	kamezawa.hiroyu@jp.fujitsu.com, aarcange@redhat.com,
	hughd@google.com, jamesjer@betterlinux.com, marcus@bluehost.com,
	matt@bluehost.com, tytso@mit.edu, shaohua.li@intel.com,
	P@draigBrady.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 0/2] fadvise: support POSIX_FADV_NOREUSE
Date: Mon, 27 Jun 2011 16:42:39 +0900	[thread overview]
Message-ID: <4E08346F.3070203@jp.fujitsu.com> (raw)
In-Reply-To: <20110627071139.GC1247@thinkpad>

>>>  POSIX_FADV_DONTNEED = drop page cache if possible
>>>  POSIX_FADV_NOREUSE = reduce page cache eligibility
>>
>> Eeek.
>>
>> Your POSIX_FADV_NOREUSE is very different from POSIX definition.
>> POSIX says,
>>
>>        POSIX_FADV_NOREUSE
>>               Specifies that the application expects to access the specified data once  and  then
>>               not reuse it thereafter.
>>
>> IfI understand correctly, it designed for calling _before_ data access
>> and to be expected may prevent lru activation. But your NORESE is designed
>> for calling _after_ data access. Big difference might makes a chance of
>> portability issue.
> 
> You're right. NOREUSE is designed to implement drop behind policy.
> 
> I'll post a new patch that will plug this logic in DONTNEED (like the
> presious version), but without breaking the old /proc/sys/vm/drop_caches
> behavior.

Great!

thanks.




WARNING: multiple messages have this Message-ID (diff)
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: andrea@betterlinux.com
Cc: akpm@linux-foundation.org, minchan.kim@gmail.com,
	riel@redhat.com, peterz@infradead.org, hannes@cmpxchg.org,
	kamezawa.hiroyu@jp.fujitsu.com, aarcange@redhat.com,
	hughd@google.com, jamesjer@betterlinux.com, marcus@bluehost.com,
	matt@bluehost.com, tytso@mit.edu, shaohua.li@intel.com,
	P@draigBrady.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 0/2] fadvise: support POSIX_FADV_NOREUSE
Date: Mon, 27 Jun 2011 16:42:39 +0900	[thread overview]
Message-ID: <4E08346F.3070203@jp.fujitsu.com> (raw)
In-Reply-To: <20110627071139.GC1247@thinkpad>

>>>  POSIX_FADV_DONTNEED = drop page cache if possible
>>>  POSIX_FADV_NOREUSE = reduce page cache eligibility
>>
>> Eeek.
>>
>> Your POSIX_FADV_NOREUSE is very different from POSIX definition.
>> POSIX says,
>>
>>        POSIX_FADV_NOREUSE
>>               Specifies that the application expects to access the specified data once  and  then
>>               not reuse it thereafter.
>>
>> IfI understand correctly, it designed for calling _before_ data access
>> and to be expected may prevent lru activation. But your NORESE is designed
>> for calling _after_ data access. Big difference might makes a chance of
>> portability issue.
> 
> You're right. NOREUSE is designed to implement drop behind policy.
> 
> I'll post a new patch that will plug this logic in DONTNEED (like the
> presious version), but without breaking the old /proc/sys/vm/drop_caches
> behavior.

Great!

thanks.



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  reply	other threads:[~2011-06-27  7:45 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-24 13:49 [PATCH v3 0/2] fadvise: support POSIX_FADV_NOREUSE Andrea Righi
2011-06-24 13:49 ` Andrea Righi
2011-06-24 13:49 ` [PATCH v3 1/2] mm: introduce __invalidate_mapping_pages() Andrea Righi
2011-06-24 13:49   ` Andrea Righi
2011-06-26 22:46   ` Rik van Riel
2011-06-26 22:46     ` Rik van Riel
2011-06-27  7:05     ` Andrea Righi
2011-06-27  7:05       ` Andrea Righi
2011-06-24 13:49 ` [PATCH v3 2/2] fadvise: implement POSIX_FADV_NOREUSE Andrea Righi
2011-06-24 13:49   ` Andrea Righi
2011-06-26 22:47   ` Rik van Riel
2011-06-26 22:47     ` Rik van Riel
2011-06-27  7:05     ` Andrea Righi
2011-06-27  7:05       ` Andrea Righi
2011-06-27  3:04 ` [PATCH v3 0/2] fadvise: support POSIX_FADV_NOREUSE KOSAKI Motohiro
2011-06-27  3:04   ` KOSAKI Motohiro
2011-06-27  7:11   ` Andrea Righi
2011-06-27  7:11     ` Andrea Righi
2011-06-27  7:42     ` KOSAKI Motohiro [this message]
2011-06-27  7:42       ` KOSAKI Motohiro
2011-06-27 10:17     ` Pádraig Brady
2011-06-27 10:17       ` Pádraig Brady
2011-06-27 10:29       ` Andrea Righi
2011-06-27 10:29         ` Andrea Righi
2011-06-27 11:53         ` Pádraig Brady
2011-06-27 11:53           ` Pádraig Brady
2011-06-27 12:39           ` Andrea Righi
2011-06-27 12:39             ` Andrea Righi
2011-07-12 21:52             ` Patrick J. LoPresti
2011-07-12 22:22               ` Andrea Righi
2011-07-13  0:36                 ` Patrick J. LoPresti

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